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Postgres FD Implementation
Commit 9d645fd8 authored by Tom Lane's avatar Tom Lane
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Support syncing WAL log to disk using either fsync(), fdatasync(), 

O_SYNC, or O_DSYNC (as available on a given platform).  Add GUC parameter
to control sync method.
Also, add defense to XLogWrite to prevent it from going nuts if passed
a target write position that's past the end of the buffers so far filled
by XLogInsert.
parent 4eb5e27a
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Showing with 287 additions and 62 deletions
doc/src/sgml/runtime.sgml
View file @ 9d645fd8
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.56 2001/03/13 01:17:05 tgl Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.57 2001/03/16 05:44:33 tgl Exp $
-->
<Chapter Id="runtime">
......@@ -1224,8 +1224,8 @@ env PGOPTIONS='-c geqo=off' psql
<term>WAL_BUFFERS (<type>integer</type>)</term>
<listitem>
<para>
Number of disk-page buffers for WAL log. This option can only be set
at server start.
Number of disk-page buffers in shared memory for WAL log.
This option can only be set at server start.
</para>
</listitem>
</varlistentry>
......@@ -1250,6 +1250,23 @@ env PGOPTIONS='-c geqo=off' psql
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>WAL_SYNC_METHOD (<type>string</type>)</term>
<listitem>
<para>
Method used for forcing WAL updates out to disk. Possible
values are
<literal>FSYNC</> (call fsync() at each commit),
<literal>FDATASYNC</> (call fdatasync() at each commit),
<literal>OPEN_SYNC</> (write WAL files with open() option O_SYNC), or
<literal>OPEN_DATASYNC</> (write WAL files with open() option O_DSYNC).
Not all of these choices are available on all platforms.
This option can only be set at server start or in the
<filename>postgresql.conf</filename> file.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</sect2>
......
doc/src/sgml/wal.sgml
View file @ 9d645fd8
<!-- $Header: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v 1.4 2001/03/13 01:17:05 tgl Exp $ -->
<!-- $Header: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v 1.5 2001/03/16 05:44:33 tgl Exp $ -->
<chapter id="wal">
<title>Write-Ahead Logging (<acronym>WAL</acronym>)</title>
......@@ -281,15 +281,6 @@
<command>CHECKPOINT</command>.
</para>
<para>
Setting the <varname>WAL_DEBUG</varname> parameter to any non-zero
value will result in each <function>LogInsert</function> and
<function>LogFlush</function> <acronym>WAL</acronym> call being
logged to standard error. At present, it makes no difference what
the non-zero value is. This option may be replaced by a more
general mechanism in the future.
</para>
<para>
The <varname>COMMIT_DELAY</varname> parameter defines for how many
microseconds the backend will sleep after writing a commit
......@@ -304,6 +295,24 @@
ten milliseconds, so that any nonzero <varname>COMMIT_DELAY</varname>
setting between 1 and 10000 microseconds will have the same effect.
</para>
<para>
The <varname>WAL_SYNC_METHOD</varname> parameter determines how
Postgres will ask the kernel to force WAL updates out to disk.
All the options should be the same as far as reliability goes,
but it's quite platform-specific which one will be the fastest.
Note that this parameter is irrelevant if <varname>FSYNC</varname>
has been turned off.
</para>
<para>
Setting the <varname>WAL_DEBUG</varname> parameter to any non-zero
value will result in each <function>LogInsert</function> and
<function>LogFlush</function> <acronym>WAL</acronym> call being
logged to standard error. At present, it makes no difference what
the non-zero value is. This option may be replaced by a more
general mechanism in the future.
</para>
</sect1>
</chapter>
......
src/backend/access/transam/xlog.c
View file @ 9d645fd8
This diff is collapsed.
src/backend/utils/misc/guc.c
View file @ 9d645fd8
......@@ -4,7 +4,7 @@
* Support for grand unified configuration scheme, including SET
* command, configuration file, and command line options.
*
* $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.32 2001/03/13 01:17:06 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.33 2001/03/16 05:44:33 tgl Exp $
*
* Copyright 2000 by PostgreSQL Global Development Group
* Written by Peter Eisentraut <peter_e@gmx.net>.
......@@ -20,6 +20,7 @@
#include "utils/guc.h"
#include "access/xlog.h"
#include "commands/async.h"
#include "libpq/auth.h"
#include "libpq/pqcomm.h"
......@@ -33,23 +34,17 @@
#include "tcop/tcopprot.h"
/* XXX should be in a header file */
/* XXX these should be in other modules' header files */
extern bool Log_connections;
extern int CheckPointSegments;
extern int CheckPointTimeout;
extern int XLOGbuffers;
extern int XLOGfiles;
extern int XLOG_DEBUG;
extern int CommitDelay;
extern int CommitSiblings;
extern bool FixBTree;
#ifdef ENABLE_SYSLOG
extern char *Syslog_facility;
extern char *Syslog_ident;
bool check_facility(const char *facility);
static bool check_facility(const char *facility);
#endif
/*
......@@ -138,7 +133,8 @@ struct config_string
GucContext context;
char **variable;
const char *default_val;
bool (*parse_hook)(const char *);
bool (*parse_hook)(const char *proposed);
void (*assign_hook)(const char *newval);
};
......@@ -330,25 +326,29 @@ static struct config_string
ConfigureNamesString[] =
{
{"krb_server_keyfile", PGC_POSTMASTER, &pg_krb_server_keyfile,
PG_KRB_SRVTAB, NULL},
{"unix_socket_group", PGC_POSTMASTER, &Unix_socket_group,
"", NULL},
PG_KRB_SRVTAB, NULL, NULL},
#ifdef ENABLE_SYSLOG
{"syslog_facility", PGC_POSTMASTER, &Syslog_facility,
"LOCAL0", check_facility},
"LOCAL0", check_facility, NULL},
{"syslog_ident", PGC_POSTMASTER, &Syslog_ident,
"postgres", NULL},
"postgres", NULL, NULL},
#endif
{"unix_socket_group", PGC_POSTMASTER, &Unix_socket_group,
"", NULL, NULL},
{"unix_socket_directory", PGC_POSTMASTER, &UnixSocketDir,
"", NULL},
"", NULL, NULL},
{"virtual_host", PGC_POSTMASTER, &VirtualHost,
"", NULL},
"", NULL, NULL},
{NULL, 0, NULL, NULL, NULL}
{"wal_sync_method", PGC_SIGHUP, &XLOG_sync_method,
XLOG_sync_method_default,
check_xlog_sync_method, assign_xlog_sync_method},
{NULL, 0, NULL, NULL, NULL, NULL}
};
/******** end of options list ********/
......@@ -723,7 +723,10 @@ set_config_option(const char * name, const char * value, GucContext
elog(elevel, "out of memory");
return false;
}
free(*conf->variable);
if (conf->assign_hook)
(conf->assign_hook)(str);
if (*conf->variable)
free(*conf->variable);
*conf->variable = str;
}
}
......@@ -737,7 +740,10 @@ set_config_option(const char * name, const char * value, GucContext
elog(elevel, "out of memory");
return false;
}
free(*conf->variable);
if (conf->assign_hook)
(conf->assign_hook)(str);
if (*conf->variable)
free(*conf->variable);
*conf->variable = str;
}
break;
......@@ -855,7 +861,7 @@ ParseLongOption(const char * string, char ** name, char ** value)
#ifdef ENABLE_SYSLOG
bool
static bool
check_facility(const char *facility)
{
if (strcasecmp(facility,"LOCAL0") == 0) return true;
......
src/backend/utils/misc/postgresql.conf.sample
View file @ 9d645fd8
......@@ -107,6 +107,8 @@
#
#wal_buffers = 8 # min 4
#wal_files = 0 # range 0-64
#wal_sync_method = fsync # fsync or fdatasync or open_sync or open_datasync
# Note: default wal_sync_method varies across platforms
#wal_debug = 0 # range 0-16
#commit_delay = 0 # range 0-100000
#commit_siblings = 5 # range 1-1000
......
src/include/access/xlog.h
View file @ 9d645fd8
......@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: xlog.h,v 1.20 2001/03/13 20:32:37 tgl Exp $
* $Id: xlog.h,v 1.21 2001/03/16 05:44:33 tgl Exp $
*/
#ifndef XLOG_H
#define XLOG_H
......@@ -176,6 +176,15 @@ extern StartUpID ThisStartUpID; /* current SUI */
extern bool InRecovery;
extern XLogRecPtr MyLastRecPtr;
/* these variables are GUC parameters related to XLOG */
extern int CheckPointSegments;
extern int XLOGbuffers;
extern int XLOGfiles;
extern int XLOG_DEBUG;
extern char *XLOG_sync_method;
extern const char XLOG_sync_method_default[];
extern XLogRecPtr XLogInsert(RmgrId rmid, uint8 info, XLogRecData *rdata);
extern void XLogFlush(XLogRecPtr RecPtr);
......@@ -202,4 +211,7 @@ extern void GetRedoRecPtr(void);
*/
extern XLogRecPtr GetUndoRecPtr(void);
extern bool check_xlog_sync_method(const char *method);
extern void assign_xlog_sync_method(const char *method);
#endif /* XLOG_H */
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